This invention relates to an apparatus for monitoring a drive signal used to drive an actuator.
Signal monitoring apparatus have been proposed, for example, in Japanese patent Kokai No. 56-54518, for monitoring a drive signal used to drive an actuator in order to check faults which may occur in the control system including the actuator. The drive signal is sampled at predetermined time intervals and the sample values are stored into a memory in a time-sharing fashion so that temporary or intermittent faults can also be checked from the stored data. Since the drive signal should be sampled at a high sampler rate to ensure reliable fault checks, the conventional apparatus requires a high-speed signal sampling device and a great-capacity memory.